Circuit Description
The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, (through Motor Control A or Motor Control B, the ground is provided by the opposing motor control circuit and then grounded through the transfer case shift control module ground circuit), the motor, through a series of gears, rotates a shaft which moves the mode and range forks to shift the transfer case between 4H, 2HI, and 4L ranges.
This DTC detects a short or open in the battery positive voltage circuit, ground circuit, an internal short in the motor windings and related circuitry, or an internal transfer case shift control module failure.
Action Taken When the DTC Sets
In the event that one of the motor control circuits is energized (battery voltage is applied) the transfer case shift control module will energize the other motor control circuit to keep the motor from running. All switch indicator lamps will flash continuously to prompt the driver that service is required. The transfer case system will be disabled and the transfer case shift control module will remain energized even with the ignition in the OFF position.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present and a momentary loss of battery power at the battery positive voltage circuit.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests the battery positive voltage circuit for an open or high resistance.
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This step inspects the T CASE fuse for an open.
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This step tests the ground circuit.
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This step tests the Motor Control A and B circuits.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform A Diagnostic System Check - Transfer Case? | -- | Go to Step 2 | |
Is the voltage within the specified values? | B+ | Go to Step 6 | Go to Step 3 | |
Inspect the T CASE fuse 20A. Is the fuse blown? | -- | Go to Step 5 | Go to Step 4 | |
4 | Repair the battery positive voltage circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 11 | -- |
5 | Repair the battery positive voltage circuit for a short to voltage or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Replace the T CASE fuse. Is the repair complete? | -- | Go to Step 11 | -- |
Connect a test lamp from the battery positive voltage circuit to the ground circuit at the transfer case shift control module. Does the test lamp light? | -- | Go to Step 8 | Go to Step 7 | |
7 | Repair the ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 11 | -- |
Is the voltage within the specified values? | +12V/-12V | Go to Step 9 | Go to Step 10 | |
9 | Repair the open or high resistance in the transfer case motor control A or B circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If ok, replace motor/encoder. Refer Motor/Encoder Replacement . Is the repair complete? | -- | Go to Step 11 | -- |
10 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Is the replacement complete? | -- | Go to Step 11 | -- |
11 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
